1. Field of the Invention
The present invention relates to an information processing apparatus and a control method therefor, and, in particular, to an information processing apparatus having a plurality of information processing parts, with a phase adjusting device provided for each thereof, and a control method thereof.
2. Description of the Related Art
For example, in a data transmission system in which data transmission is carried out among a plurality of integrated circuits such as LSI circuits, a configuration is known in which flip-flop circuit devices or such are used on a reception side, a data signal and a clock signal, i.e., a timing signal, are received there. On the reception side, the data signal is taken in timing of the clock signal (see Japanese Laid-Open Patent Application 2000-163963).
In this case, in order that the flip-flop circuit device can positively take the received data signal, input of the data signal should be carried out in such a timing avoiding a set-up time and a hold time of the clock signal as well-known. For this purpose, such a control should be carried out that a phase between the data signal and the clock signal may meet predetermined requirements. For this purpose, a phase adjusting device may be provided on a signal receiving part, as a well-known art.
In this phase adjusting device, in order to adjust the phase relationship between the received data signal and the received clock signal by means of a phase adjusting operation, any one of the data signal and the clock signal is delayed. After the phase relationship therebetween becomes thus meeting the predetermined requirements through such a phase adjusting operation, an operation of actually taking the data signal is carried out by the above-mentioned flip-flop circuit device is started.
Such a phase adjusting operation in the reception-side LSI circuit is carried out regularly during data transmission. As to the phase adjusting operation, merely a slight phase error correction is required when the signal transmission condition is stable. However, in a case where a phase adjustment is carried out when power supply is started in a transmission-side LSI circuit for example, a certain time period may be required until such a stable signal transmission condition is reached.